This article is published in Journal of Molecular Recognition as a special issue on Affinity 2009 edited by Gideon Fleminger, Tel-Aviv University, Tel-Aviv, Israel and George Ehrlich, Hoffmann-La Roche, Nutley, NJ, USA.
Proteolysis activity of IgM antibodies from rheumatoid arthritis patients' sera: evidence of atypical catalytic site†
Version of Record online: 28 OCT 2010
Copyright © 2010 John Wiley & Sons, Ltd.
Journal of Molecular Recognition
Special Issue: Affinity 2009 – The 18th biennial meeting of the International Society for Molecular Recognition
Volume 23, Issue 6, pages 577–582, November/December 2010
How to Cite
Kamalanathan, A. S., Goulvestre, C., Weill, B. and Vijayalakshmi, M. A. (2010), Proteolysis activity of IgM antibodies from rheumatoid arthritis patients' sera: evidence of atypical catalytic site. J. Mol. Recognit., 23: 577–582. doi: 10.1002/jmr.1035
- Issue online: 28 OCT 2010
- Version of Record online: 28 OCT 2010
- Manuscript Accepted: 5 FEB 2010
- Manuscript Revised: 1 FEB 2010
- Manuscript Received: 30 NOV 2009
- IgM purification;
- monolith chromatography;
- nucleic acid hydrolysis;
- peptidase activity;
- rheumatoid factor
The IgM antibodies from rheumatoid arthritis (RA) patients' sera were screened for peptide hydrolyzing activity. Recovery of structurally intact IgM antibodies (Abs), in a single step, was achieved using a weak anion-exchange methacrylate monolith disk. The IgM Abs from patients' sera hydrolyzed the Pro-Phe-Arg-4-methyl-coumaryl-7-amide (PFR-MCA) substrate appreciably compared to the healthy donors. The apparent Km values of IgM Abs from patients' sera were between 0.4 and 0.7 mM. Furthermore, IgM Abs displayed 5 to 10-folds greater proteolysis activity than IgG Abs, recovered from the same pathological serum. The proteolysis activity, as a function, was found to be independent of IgM-RF titer value. Affinity labeling approach targeted at the catalytic site histidine was studied, using a specific irreversible inhibitor, N-α-tosyl-L-lysine chloromethyl ketone (TLCK). Despite modification of catalytic His, observation of serine protease like activity suggest presence of an atypical catalytic framework in a few pathological IgM Abs. Copyright © 2010 John Wiley & Sons, Ltd.